Merged revision(s) 20335 from trunk/OpenMPT:

[Fix] mpt/io_read/filedata_base_unseekable.hpp: Avoid memory denial-of-service when trying to read way more data than the actual file size from unseekable files.
........


git-svn-id: https://source.openmpt.org/svn/openmpt/branches/OpenMPT-1.31@20340 56274372-70c3-4bfc-bfc3-4c3a0b034d27

src/mpt/io_read/filedata_base_unseekable.hpp

@@ -87,15 +87,14 @@ class FileDataUnseekable : public IFileData {
  return;
  }
  std::size_t alignedpos = mpt::saturate_align_up<std::size_t>(target, QUANTUM_SIZE);
- std::size_t needcount = alignedpos - cachesize;
- EnsureCacheBuffer(needcount);
- std::size_t readcount = InternalReadUnseekable(mpt::span(&cache[cachesize], alignedpos - cachesize)).size();
- cachesize += readcount;
- if (!InternalEof()) {
-  // can read further
- return;
+ while (!InternalEof() && (cachesize < alignedpos)) {
+  EnsureCacheBuffer(BUFFER_SIZE);
+  std::size_t readcount = InternalReadUnseekable(mpt::span(&cache[cachesize], BUFFER_SIZE)).size();
+  cachesize += readcount;
+ }
+ if (InternalEof()) {
+ streamFullyCached = true;
  }
- streamFullyCached = true;
  }
 
 private: